José Valim from PlataformaTec just released a screencast about RailsMetrics. RailsMetrics is a Rails 3 engine which listens to ActiveSupport::Notifications and store them in the database, so you can know what is happening in your application at each request and create some charts and statistics. In this screencast, José Valim shows how to install it, takes a quick look at the source code and tell you how you can make RailsMetrics even better.